Generator Protection Class presentation
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Transcript of Generator Protection Class presentation
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7/28/2019 Generator Protection Class presentation
1/123
Completed by :Mohammad Ibnul Hossain
Executive Engineer (Operation)Tongi 80(105) MW GT Power Station
Bangladesh Power Development BoardE-mail : [email protected]
GENERATOR PROTECTION
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Possible Faults
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Abnormal operating condition
overcurrent / overload unbalanced load
over temperature over- and undervoltage over- and underexcitation
over- and underfrequency
over-fluxing
asynchronous running
out of step
generator motoring failures in the machine control system (i.e. AVR orgovernor failure)
failures in the machine cooling system
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In abnormal condition ,
those dont need immediate trip the unit generator
Or transformer but cant continue , at some stage
we must trip-out the system.
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Different Power Plant Electrical Layout
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Damage to the stator core in case of earth-fault
The stator cant withstand with a small amount of ground current evenWith short period of time.
Arrangement must be taken to limit the ground fault current not more
than 10 amp.
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How it is done ?
it is achieved by grounding
Here we see different types of alternatives.
Solidly grounded through a resistor typically in Europe
Grounding transformer , typically for U.S
Stator winding Earthing Practice :
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87 Differential59 over -voltages
24V/HZ over fluxing
49S stator Over load
51 over -current
64s Ground Fault stator
Inter-turn
64R Ground fault Rotor
71 pole slipping
40 Loss of excitation
32 Reverse Power81 O/U Frequency
Turbine
Rotor Stator
Allocation of Protection Function
46 Negative Phase Sequence
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No.DESCRIPTION
2Time-delay relay
21
Distance relay24
Over excitation / Volts per Hertz
25 Synchronism-check relay
27 Under voltage relay
27TN Third-Harmonic Under voltage relay
30 Annunciator device
32 Reverse power relay
37 Undercurrent or underpower relay
40 Field excitation relay
46 Negative sequence overcurrent relay
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47 Negative sequence overvoltage relay
49 Thermal relay
50 instantaneous AC overcurrent relay
50DT Split Phase Differential
50/27 inadvertent Energizing
50BF Breaker Failure
51 AC Inverse Time Overcurrent relay
52 Circuit breaker
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59Overvoltage relay
59DThird-Harmonic Voltage Differential Ratio
60 Voltage balance or loss of potential relay
63 Pressure device
64F Field Ground relay
64B Brush Lift-Off Detection
64S100% Stator Ground Protection by LowFrequency Injection
67 AC directional overcurrent relay
68 Power Swing Blocking
69Permissive relay
59N Single Phase Overvoltage Relay
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74 Alarm relay
76 DC overcurrent relay
78 Out-of-step relay
79 AC reclosing relay
81 Frequency relay
81R Rate of Change Frequency relay
83 Transfer device
85 Carrier or pilot-wire relay
86 Lock out relay
87 Differential relay
94 Auxiliary tripping relay
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Consequence of stator short circuit
Insulation. windings and stator core can be
damaged
Large forces, caused by large fault currents. can
give damage to other components in the plant
Risk of explosion and fire
Mechanical stress on generator- and turbine
shafts
Stator Short Circuit
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Detection of stator short circuits
Protection functions Generator differential protection
Unit differential protection Directional negative sequence overcurrent
protection
Under impedance protection
Phase overcurrent protection Voltage dependent phase overcurrent protection Under voltage protection
Phase overcurrent protection of the unit
transformer
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Phase to phase fault in the stator winding
Endangering condition
Overcurrent Protected object
Stator winding
Consequences Heating Forces
Smelted stator core
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87Oo/a Diff
51
OC
50/51
OC
YY
YY
51OC
60
FL81
Freq.rel.
50
Ac.Eneg
GENERATOR AND UNIT TRANS FORMER UNIT SCHEME
51/67
OC(Idm/dir.)
50
Neg.Pha.
87G
Gen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S
100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37
Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.
64S
100%GFP+ REX0061
UnitX
for.
46
Neg.Pha.
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87ODiff(x-f)
51
OC
50/51
OC
YY
YY
51OC
60
FL81
Freq.rel.
50
Ac.Eneg
GENERATOR AND UNIT TRANS FORMER UNIT SCHEME
51/67
OC(Idm/dir.)
50
Neg.Pha.
87G
Gen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S
100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Distance
32
Rev. Pow.
37
Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.
64S
100%GFP+ REX0061
UnitX
for.
87Oo/a Diff
Udr.Imp.pro.
46
Neg.Pha.
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87ODiff(x-f)
51
OC
50/51
OC
YY
YY
51OC
60
FL81
Freq.rel.
50
Ac.Eneg
GENERATOR AND UNIT TRANS FORMER UNIT SCHEME
51/67
OC(Idm/dir.)
50
Neg.Pha.
87GGen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S
100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Distance
32
Rev. Pow.
37
Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.
64S
100%GFP+ REX0061
UnitX
for.
87Oo/a Diff
Udr.Imp.pro.
46
Neg.Pha.
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87ODiff(x-f)
51
OC
50/51
OC
YY
YY
51OC
60
FL81
Freq.rel.
50
Ac.Eneg
GENERATOR AND UNIT TRANS FORMER UNIT SCHEME
51/67
OC(Idm/dir.)
50
Neg.Pha.
87GGen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S
100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Distance
32
Rev. Pow.
37
Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.
64S
100%GFP+ REX0061
UnitX
for.
87Oo/a Diff
Udr.Imp.pro.
46
Neg.Pha.
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87ODiff(x-f)
51
OC
50/51
OC
YY
YY
51OC
60
FL81
Freq.rel.
50
Ac.Eneg
GENERATOR AND UNIT TRANS FORMER UNIT SCHEME
51/67
OC(Idm/dir.)
50
Neg.Pha.
87GGen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S
100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Distance
32
Rev. Pow.
37
Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.
64S
100%GFP+ REX0061
UnitX
for.
87Oo/a Diff
Udr.Imp.pro.
46
Neg.Pha.
Diff ti l P t ti
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Let us , Consider , X protected EquipmentCT1 and CT2 same transformation ratioThe current flow in the primary and secondary sides of power
transformer are identical, assuming ideal transformer.The secondary current i1 and i2 are equal in magnitude and oppositein direction.So, the net current in the differential coil is zero at load condition
(without fault), and the relay will not operate .
Differential Protection
XI1 I2
i1i2
TC
i1
i2
i1 i2
Diff. Relay
CT1 CT2
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Differential Protection
XI1 I2
i1
i2
TC
i1
i2
i1 i2
Diff. Relay
CT1 CT2
External Fault happens ,
Then , I1 and I2 increases as well as i1 and i2 increasesBut the phase angle of i1 and i2 will be the same ,
So , the net current in the TC or Operating Coil = 0
So, the relay will not operate
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XI1 I2
i1
i2
TC
i1
i2
i1 i2
Diff. Relay
CT1 CT2
Differential Protection
is another source to feed the fault ,
So I2 0 ,
I diff = i1 + i2 which is very highAnd trips the Differential Relay
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Biased differential relay
XI1 I2
i1
i2
Op
i1
i2
i1 i2
Biased Diff. Relay
CT1 CT2
Res. Res.
Large external fault cause false operation
To make more stable Two Restraining ( Biasing ) coilAndOne Operating coil is introduced .What is the function of two Restraining ( Biasing ) Coils ?Restraining coils will oppose the operation of operating coil.
The relay will operate only when the operating force > the restraining force
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Tripping Characteristics of Simple Differential Relay
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Tripping Characteristics of Biased Differential Relay with TwoStages (Two Slops )
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Connections of CTs for differential protection of generator.
Percentage differential relaying of a star connected generator , for phase-phase faults.
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Percentage differential relay of a delta connected generator ,forphase-phase fault.
G diff i l i O h h
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Generator differential protection Operates then what
happens ?
Shall trip the followings :
Turbine: close down active power
Generator breaker: if available
Field breaker
Unit breaker: If no generator breaker Fire protection
Differential Protection can be used :
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Differential Protection can be used :
The layout of what we are talking about 87G the differentialprotection of gen87T- the differential protection of step-uptransformer870- both the generator and the step-up transformer.
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Endangering condition Overcurrent
Protected object
Transformer windings
Consequences
Heating
Forces
Smelted transformer core
Phase to phase fault in the transformer winding
h h f l h f d
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87Oo/a Diff
51OC
50/51
OC
YY
YY
51OC
60
FL81
Freq.rel.
50
Ac.Eneg
Phase to phase fault in the transformer winding
51/67
OC(Idm/dir.)
50
Neg.Pha.
87GGen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37
Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.64S
100%GFP
+ REX0061
UnitX
for.
46
Neg.Pha.
Ph h f l i h f i di
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87Oo/a Diff
51OC
50/51
OC
YY
YY
51OC
60
FL81
Freq.rel.
50
Ac.Eneg
Phase to phase fault in the transformer winding
51/67
OC(Idm/dir.)
50
Neg.Pha.
87GGen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37
Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.64S
100%GFP
+ REX0061
UnitX
for.
46
Neg.Pha.
Ph h f l i h f i di
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87Oo/a Diff
51OC
50/51
OC
YY
YY
51OC
60
FL81
Freq.rel.
50
Ac.Eneg
Phase to phase fault in the transformer winding
51/67
OC(Idm/dir.)
50
Neg.Pha.
87GGen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.64S
100%GFP
+ REX0061
UnitX
for.
46
Neg.Pha.
Ph t h f lt i th t f i di
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87Oo/a Diff
51OC
50/51
OC
YY
YY
51OC
60
FL81
Freq.rel.
50
Ac.Eneg
Phase to phase fault in the transformer winding
51/67
OC(Idm/dir.)
50
Neg.Pha.
87GGen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.64S
100%GFP
+ REX0061
UnitX
for.
46
Neg.Pha.
fault impedance < load impedance
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fault impedance < load impedanceSo , the fault current > load current.If a short circuit occursthe circuit impedancetherefore a fault is accompanied by large current
Overcurrent relays sense fault currents and also over-loadcurrents.Overcurrent protection is that protection in which the relay picksup when the magnitude of current exceeds the pickup level.The basic element in overcurrent protection is an overcurrent relay.
The overcurrent relays are connected to the system, normally bymeans of CTs. Overcurrent
relaying has following types :- High speed overcurrent protection.- Definite time overcurrent protection.- Inverse minimum time overcurrent protection.
- Directional overcurrent protection (or above any type)
Over-current protection includes the protection from
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Over current protection includes the protection from
overloads .
Overloading of a machine or equipment means the machineis taking Current > rated current .
Hence with overloading , there is an associated temperature
rise .
Overcurrent protection of overloads is generally provided by
thermal relay.
The permissible rise has limit based on insulation class and
material problems.
Over-current protection includes short-circuit protection
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Over current protection includes short circuit protection.
Short circuits can bephase faults
earth faultswinding faults.
Short-circuit currents are generally several times (5 to 20) full
load current.
Fast fault clearance is always desirable on short-circuits
When a machine is protected by differential protection, theover-current is provided in addition as a back-up and in somecases to protect the machine from sustained through fault.
Several protective devices are used for over-current
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Several protective devices are used for over current
protection .
These includes
-Fuses
-Miniature circuit-breakers, molded-case circuit-breakers.
-Circuit-breakers fitted with overloaded coils or tripped byover-current relays.
-Series connected trip coils operating switching devices.
- Over-current relays in conjunction with current
transformers.
Th i i t f t t ti
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The primary requirements of over-current protection are :
The protection should not operate starting currents
permissible overcurrentCurrent surges.
To achieve this
The time delay is provided (in case of inverse relays)If time delay cannot be permitted
high-set instantaneous relaying is used.
- The protection should be co-ordinated with neighbouringover-current protections
CHARACTERISTICS OF RELAY UNITS FOR OVER-CURRENT
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PROTECTION
There is a wide variety of relay-units. These are classified
according to their type and characteristics.
The major characteristic include :
- Definite characteristic
- Extremely Inverse
-Inverse- Inverse characteristic
- Very Inverse
Inverse characteristic
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Inverse characteristic
t 1 / Iwhere I= Current in relay coil
t = Relay limeK = Constant
Very Inverse characteristic
t 1 / Inwhere n = 2 to 8 , according to the requirements.
Connection Scheme withThree Over current Relays
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. Connection Scheme withThree Over-currentRelays
Relay Coil
OvercurrentRelayCB
R Y B
IR IY IB +
AUXILLARYSWITCH
TripCoil
RelayContact
Connection Scheme withThree Over-currentRelays
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Relay Coil
OvercurrentRelay
CB
R YB
IR IY IB
+
AUXILLARYSWITCH
TripCoil
RelayContact
+ DEFINITETIMERELAY
AUXILLARYRELAY
ywith addition of a common time-delay relayand an auxiliary relay
Stator earth fault
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Stator earth fault
Damages on the stator iron
Increased voltage on healthy phases
Small fault currents
Sensitivity requirements on fault clearance
The fault resistance is normally low atstator earth fault
RESTRICTED EARTH-FAULT PROTECTION BY DIFFERENTIAL SYSTEM
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RESTRICTED EARTH FAULT PROTECTION BY DIFFERENTIAL SYSTEM
, Neutral is earthed through resistance to limit earth-fault currents.
With resistance earthing, it is not possible to protect complete winding from earth-fault andthe % of winding protected depends on the value of neutral earthing resistor and the relaysettingSetting Criteria :
The current rating of resistor, resistance value, relay setting, etc. should be selectedcarefully.Setting should be such that the protection does not operate for earth-faults on EHV
side
RESTRICTED EARTH-FAULT PROTECTION BY DIFFERENTIAL SYSTEM (Cont.) a
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RESTRICTED EARTH FAULT PROTECTION BY DIFFERENTIAL SYSTEM (Cont.) a
Setting Criteria (Cont.) :
Earth faults are not likely to occur near the neutral point due to less voltage w.r.t. earth.It is a usual practice to protect about 80 to 85% of generator winding against earth-faults.
It is a usual practice to protect about 80 to 85% of generator winding against earth-faults.
The remaining 20 to 5% winding from neutral side left unprotected by the differentialprotection.
In additional to differential protection, a separate earth-fault protection is provided to take
care of the complete winding against earth faults.
RESTRICTED EARTH-FAULT PROTECTION BY DIFFERENTIAL SYSTEM (Cont.) a
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( )
During earth-fault the current, Ifflows through a part of the generator winding and
neutral to ground circuit.
The corresponding secondary current Is flows through the operating coil andrestricted earth-fault coil of the differential protection.
The setting of the restricted earth fault relay can be selected independent of the
setting of the overcurrent relay.
RESTRICTED EARTH-FAULT PROTECTION BY DIFFERENTIAL SYSTEM (Cont.)
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( )
Here, fault at pointf , Iffault current , VafVoltage
If fault is nearer to neutral point Vafis relatively less .Hence , If is reduced .Not practicable for too sensitive setting , because it will operate in through fault of smallMagnitude for inaccurate CT and saturation of CT.
Practice to provide 85% protection , the rest 15% is protected by another scheme.
Discuss Next.
100% STATOR EARTH-FAULT PROTECTION
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100% STATOR EARTH FAULT PROTECTION
Coupling TransformerGround Circuit
Signal (12.5Hz) continuously injected Stator winding
No Fault Signal feed into stray capacitance .
IN FaultCapacitance is by-passed and monitoring
Current (of 12.5 Hz) is sensed by the measuring system.
Earth Fault in Stator Winding
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Endangering condition
Overvoltage in two healthy phases Voltage in the star point Relatively small earth fault current
Protected object Stator winding
Consequences Damage to the stator core Risk of second earth fault
Earth Fault in Stator Winding
Stator Earth Fault Protection
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87Oo/a Diff51OC
50/51
OC
Y
Y
YY
51
OC
60
FL81
Freq.rel.
50
Ac.Eneg
Stator Earth Fault Protection
51/67
OC(Idm/dir.)
50
Neg.Pha.
87GGen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.64S
100%GFP + REX0061
UnitX
for.
46
Neg.Pha.
Stator Earth Fault Protection
-
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87Oo/a Diff51OC
50/51
OC
Y
Y
YY
51
OC
60
FL81
Freq.rel.
50
Ac.Eneg
Stator Earth Fault Protection
51/67
OC(Idm/dir.)
50
Neg.Pha.
87GGen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.64S
100%GFP + REX0061
UnitX
for.
Stator Earth Fault Protection
-
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87Oo/a Diff51OC
50/51
OC
Y
Y
YY
51
OC
60
FL81
Freq.rel.
50
Ac.Eneg
Stator Earth Fault Protection
51/67
OC(Idm/dir.)
50
Neg.Pha.
87GGen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.64S
100%GFP + REX0061
UnitX
for.
46
Neg.Pha.
Stator Earth Fault Close to star point
-
7/28/2019 Generator Protection Class presentation
58/123
Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87Oo/a Diff51OC
50/51
OC
Y
Y
YY
51
OC
60
FL81
Freq.rel.
50
Ac.Eneg
Stator Earth Fault Close to star point
51/67
OC(Idm/dir.)
50
Neg.Pha.
87GGen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.64S
100%GFP + REX0061
UnitX
for.
46
Neg.Pha.
StatorEarth Fault Close to star point
-
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87Oo/a Diff51OC
50/51
OC
Y
Y
YY
51
OC
60
FL81
Freq.rel.
50
Ac.Eneg
Stato a t ault Close to sta po t
51/67
OC(Idm/dir.)
50
Neg.Pha.
87GGen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.64S
100%GFP + REX0061
UnitX
for.
46
Neg.Pha.
Earth fault in transformer HV winding
-
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f f g
Endangering condition
Overcurrent
Protected object
Transformer windings
Consequences Heating
Forces
Smelted transformer core
Earth fault in transformer HV winding
-
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87Oo/a Diff51OC
50/51
OC
Y
Y
YY
51
OC
60
FL81
Freq.rel.
50
Ac.Eneg
f f g
51/67
OC(Idm/dir.)
50
Neg.Pha.
87GGen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.64S
100%GFP + REX0061
UnitX
for.
46
Neg.Pha.
Earth fault in transformer HV winding
-
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87Oo/a Diff51OC
50/51
OC
Y
Y
YY
51
OC
60
FL81
Freq.rel.
50
Ac.Eneg
f f g
51/67
OC(Idm/dir.)
50
Neg.Pha.
87GGen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.64S
100%GFP + REX0061
UnitX
for.
46
Neg.Pha.
Earth fault in transformer HV winding
-
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87Oo/a Diff51OC
50/51
OC
Y
Y
YY
51
OC
60
FL81
Freq.rel.
50
Ac.Eneg
f f g
51/67
OC(Idm/dir.)
50
Neg.Pha.
87GGen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.64S
100%GFP + REX0061
UnitX
for.
StatorEarth Fault Protection
-
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87Oo/a Diff51OC
50/51
OC
Y
Y
YY
51
OC
60
FL81
Freq.rel.
50
Ac.Eneg51/67
OC(Idm/dir.)
50
Neg.Pha.
87GGen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.64S
100%GFP + REX0061
UnitX
for.
46
Neg.Pha.
Stator Earth fault in transformer HV winding
-
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87Oo/a Diff51OC
50/51
OC
Y
Y
YY
51
OC
60
FL81
Freq.rel.
50
Ac.Eneg
f f g
51/67
OC(Idm/dir.)
50
Neg.Pha.
87GGen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.64S
100%GFP + REX0061
UnitX
for.
46
Neg.Pha.
Earth fault in transformer HV winding
-
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87Oo/a Diff51OC
50/51
OC
Y
Y
YY
51
OC
60
FL81
Freq.rel.
50
Ac.Eneg
f f g
51/67
OC(Idm/dir.)
50
Neg.Pha.
87GGen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.64S
100%GFP + REX0061
UnitX
for.
46
Neg.Pha.
Earth fault in transformer LV winding
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Endangering condition Overvoltage in two healthy phases
Voltage in the star point Relatively small earth fault current
Protected object
Transformer winding
Consequences
Small possibility to damage transformer
core Risk of second earth fault
Earth-Fault in the LV Winding
-
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87Oo/a Diff51OC
50/51
OC
Y
Y
YY
51
OC
60
FL81
Freq.rel.
50
Ac.Eneg51/67
OC(Idm/dir.)
50
Neg.Pha.
87GGen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.64S
100%GFP + REX0061
UnitX
for.
Earth-Fault in the LV Winding
-
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87Oo/a Diff51OC
50/51
OC
Y
Y
YY
51
OC
60
FL81
Freq.rel.
50
Ac.Eneg51/67
OC(Idm/dir.)
50
Neg.Pha.
87GGen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.64S
100%GFP + REX0061
UnitX
for.
Earth-Fault in the LV Winding
-
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87Oo/a Diff51OC
50/51
OC
Y
Y
YY
51
OC
60
FL81
Freq.rel.
50
Ac.Eneg51/67
OC(Idm/dir.)
50
Neg.Pha.
87GGen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.64S
100%GFP + REX0061
UnitX
for.
Turn to turn turn fault in the stator winding :
-
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Earth-Fault in the LV Winding
-
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87Oo/a Diff51OC
50/51
OC
Y
Y
YY
59N
OV
60
FL81
Freq.rel.
50
Ac.Eneg51/67
OC(Idm/dir.)
50
Neg.Pha.
87GGen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.64S
100%GFP + REX0061
UnitX
for.
Earth-Fault in the LV Winding
-
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87Oo/a Diff51OC
50/51
OC
Y
Y
YY
59N
OV
60
FL81
Freq.rel.
50
Ac.Eneg51/67
OC(Idm/dir.)
50
Neg.Pha.
87GGen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.64S
100%GFP + REX0061
UnitX
for.
51N detected the fault whenIt developes
Earth-Fault in the LV Winding
-
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87Oo/a Diff51OC
50/51
OC
Y
Y
YY
59N
OV
60
FL81
Freq.rel.
50
Ac.Eneg51/67
OC(Idm/dir.)
50
Neg.Pha.
87GGen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.64S
100%GFP + REX0061
UnitX
for.
51N detected the fault whenIt developes
Rotor Earth Fault :
-
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The field circuit of the generator is normally isolated
from earth
With a single earth fault in the rotor circuit it is possible
to have continuous operation without generator
damages
There is however a risk of a second rotor earth fault. In
such a case there will be large current and risk of severedamages.
The requirement of fast fault clearance is moderate
-
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Earth-Fault in Rotor Winding :
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Endangering condition
None
Protected object
Rotor windingConsequences
Risk of evolving into double earth fault
g
Earth-Fault in the Rotor
-
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87Oo/a Diff51OC
50/51
OC
Y
Y
YY
59N
OV
60
FL81
Freq.rel.
50
Ac.Eneg51/67
OC(Idm/dir.)
50
Neg.Pha.
87GGen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.64S
100%GFP + REX0061
UnitX
for.
Earth-Fault in the Rotor
-
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87Oo/a Diff51OC
50/51
OC
Y
Y
YY
59N
OV
60
FL81
Freq.rel.
50
Ac.Eneg51/67
OC(Idm/dir.)
50
Neg.Pha.
87GGen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.64S
100%GFP + REX0061
UnitX
for.
-
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Loss of/Under excitation
-
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Endangering condition
Stator reactive current component
Protected object Rotor and stator winding
Consequences
Thermal damage of rotor and statorend regions
Asynchronous machine operation
Voltage and current variations
Earth-Fault in the Rotor
-
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87Oo/a Diff51OC
50/51
OC
Y
Y
YY
59N
OV
60
FL81
Freq.rel.
50
Ac.Eneg51/67
OC(Idm/dir.)
50
Neg.Pha.
87GGen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.64S
100%GFP + REX0061
UnitX
for.
Earth-Fault in the Rotor
-
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87Oo/a Diff51OC
50/51
OC
YY
YY
59N
OV
60
FL81
Freq.rel.
50
Ac.Eneg51/67
OC(Idm/dir.)
50
Neg.Pha.
87GGen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.64S
100%GFP + REX0061
UnitX
for.
Generator motoring protection
-
7/28/2019 Generator Protection Class presentation
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Generator shall produce active power (i.e. P>0)
When it starts to receive the active power it acts as a
motor (i.e. P
-
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loss of prime-mover
low water flow (hydro) load variations I problems
Effects
steam units overheating of turbine and turbine blade
hydro units cavitations of the blades
Reverse Power Protection
-
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Endangering condition
Motor operation
Protected object
Turbine
Consequences Excessive heating of turbine blades (steam units)
Mechanical damages to thrust bearing (Francisturbines) Explosion risk for diesel units
Reverse Power Protection
-
7/28/2019 Generator Protection Class presentation
87/123
Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87Oo/a Diff51OC
50/51
OC
YY
YY
59N
OV
60
FL81
Freq.rel.
50
Ac.Eneg51/67
OC(Idm/dir.)
50
Neg.Pha.
87G
Gen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.64S
100%GFP + REX0061
UnitX
for.
Reverse Power Protection
-
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87Oo/a Diff51OC
50/51
OC
YY
YY
59N
OV
60
FL81
Freq.rel.
50
Ac.Eneg51/67
OC(Idm/dir.)
50
Neg.Pha.
87G
Gen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37
Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.64S
100%GFP + REX0061
UnitX
for.
Negative sequence overcurrent
-
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From asymmetric currents, a negative sequence current
component12, is filtered out.
Negative sequence stator currents rotate in a oppositedirection from the rotor and consequently induce a
100Hz current component into the rotor.
As a consequence rotor ends can over-heat.
k is the indicator of how long (Sec.) a
generator can withstand one/unit Neg.seq.Cur.
Negative phase sequence (46)
-
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Causes
unbalanced loads untransposed transmission circuits
unbalanced system faults
series faults
CB pole discrepancy open circuits
Features
Characteristic adjustable to I22t = KK determines the right tripping time , which is
provided by the manufacturer (one/unit Neg.seq.Cur)
StatorEarth Fault Protection
-
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87Oo/a Diff51OC
50/51
OC
YY
YY
51
OC
60
FL81
Freq.rel.
50
Ac.Eneg51/67
OC(Idm/dir.)
50
Neg.Pha.
87G
Gen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37
Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.64S
100%GFP + REX0061
UnitX
for.
46
Neg.Pha.
StatorEarth Fault Protection
-
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87Oo/a Diff51OC
50/51
OC
YY
YY
51
OC
60
FL81
Freq.rel.
50
Ac.Eneg51/67
OC(Idm/dir.)
50
Neg.Pha.
87G
Gen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37
Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.64S
100%GFP + REX0061
UnitX
for.
46
Neg.Pha.
Broken stator winding
-
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Endangering condition
Unsymmetrical currents
Protected object
Stator windings
Rotor
Consequences
Rotor overheating
Vibrations
Broken transformer winding
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Endangering condition Unsymmetrical currents
Protected object Stator windings
Rotor
Consequences
Rotor overheating Vibrations
Diff l k fl
StatorEarth Fault Protection
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87Oo/a Diff51OC
50/51
OC
YY
YY
51
OC
60
FL81
Freq.rel.
50
Ac.Eneg51/67
OC(Idm/dir.)
50
Neg.Pha.
87G
Gen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37
Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.64S
100%GFP + REX0061
UnitX
for.
46
Neg.Pha.
Pole slip / out of step protection
-
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Asynchronous running of a synchronous machine with the rest ofthe system but with excitation intact
Big mechanical impact on turbine and shaft
Pole Slip typically caused by: Long fault clearance time (especially close by 3Ph faults arecritical) Inadvertent tripping of a transmission line (increase oftransmission impedance between generator and load) Loss of large generator unit
Pole slip / out of step protection
E d i diti
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Endangering condition High stator current
Possible system blackout
Protected object
Rotor shaft and stator winding
Consequences
Mechanical damages to shaft Asynchronous machine operation (withfield intact) Voltage and current variations
Diff l B k fl
Pole slip / out of step protection
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87Oo/a Diff51OC
50/51
OC
YY
YY
51
OC
60
FL81
Freq.rel.
50
Ac.Eneg51/67
OC(Idm/dir.)
50
O.C
87G
Gen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37
Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.64S
100%GFP + REX0061
UnitX
for.
46
Neg.Pha.
Diff l B k fl OC
Pole slip / out of step protection
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87Oo/a Diff51OC
50/51
OC
YY
YY
51
OC
60
FL81
Freq.rel.
50
Ac.Eneg51/67
OC(Idm/dir.)
50
Neg.Pha.
87G
Gen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37
Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.64S
100%GFP + REX0061
UnitX
for.
46
Neg.Pha.
Low frequency
-
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Endangering condition
Under-frequency
Protected object
Transformer
Steam turbine
Consequences
Over-excitation
Steam turbine vibrations
Diff rel Brk flr OC Th
Low frequency
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87Oo/a Diff51OC
50/51
OC
YY
YY
51
OC
60
FL81
Freq.rel.
50
Ac.Eneg51/67
OC(Idm/dir.)
50
O.C
87G
Gen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S
100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37
Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.64S
100%GFP + REX0061
UnitX
for.
46
Neg.Pha.
Diff rel Brk flr OC Th
Low frequency
-
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87Oo/a Diff51OC
50/51
OC
YY
YY
51
OC
60
FL81
Freq.rel.
50
Ac.Eneg51/67
OC(Idm/dir.)
50
O.C
87G
Gen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S
100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37
Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.64S
100%GFP + REX0061
UnitX
for.
46
Neg.Pha.
High Frequency
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Endangering condition
Over-frequency
Protected object Turbine
Rotor
Consequences
Mechanical stresses
Turbine vibrations
Diff rel Brk flr OC Th
Low frequency
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87O
o/a Diff51OC
50/51
OC
YY
YY
51
OC
60
FL81
Freq.rel.
50
Ac.Eneg51/67
OC(Idm/dir.)
50
O.C
87G
Gen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S
100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37
Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.64S
100%GFP + REX0061
UnitX
for.
46
Neg.Pha.
Diff rel Brk flr OC Th
Low frequency
-
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87O
o/a Diff51OC
50/51
OC
YY
YY
51
OC
60
FL81
Freq.rel.
50
Ac.Eneg51/67
OC(Idm/dir.)
50
O.C
87G
Gen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S
100%GFP
50THD
100%GFP
+ REX0060
78
Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37
Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.64S
100%GFP + REX0061
UnitX
for.
46
Neg.Pha.
-
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Over Voltage Protection:
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Endangering condition
Over-voltage Improper voltage regulation
Protected object
Electrical circuits
Consequences
Increased risk for earth-faults
Over-excitation
g
Diff rel Brk flr OC Therm
Over Voltage Protection:
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87O
o/a Diff51OC
50/51
OC
YY
YY
51
OC
60
FL81
Freq.rel.
50
Ac.Eneg51/67
OC(Idm/dir.)
50
O.C
87G
Gen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S
100%GFP
50THD
100%GFP
+ REX0060
78Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37
Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.
64S
100%GFP + REX0061
UnitX
for.
46
Neg.Pha.
Diff rel Brk flr OC Therm
Over Voltage Protection:
-
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Y
G
87 N
Diff.rel.50BFBrk.flr.
50/51
OC49
Therm.
87O
o/a Diff51OC
50/51
OC
YY
YY
51
OC
60
FL81
Freq.rel.
50
Ac.Eneg51/67
OC(Idm/dir.)
50
O.C
87G
Gen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S
100%GFP
50THD
100%GFP
+ REX0060
78Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37
Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.
64S
100%GFP + REX0061
UnitX
for.
46
Neg.Pha.
Over-fluxing
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Over fluxing protection protects generator and
transformer magnetic core against overheating
Specially critical during start-up and shut-down
Wide frequency operation of the relay important forgenerator
protection
-
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Diff.rel. Brk.flr. OC Therm
Over Voltage Protection:
-
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Y
G
87 N
e50BFBrk.flr.
50/51
OC49
Therm.
87O
o/a Diff51OC
50/51
OC
YY
YY
51
OC
60
FL81
Freq.rel.
50
Ac.Eneg51/67
OC(Idm/dir.)
50
O.C
87G
Gen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S
100%GFP
50THD
100%GFP
+ REX0060
78Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37
Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.
64S
100%GFP + REX0061
UnitX
for.
46
Neg.Pha.
-
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Diff.rel. Brk.flr. OC Therm
Stator Thermal Overload
-
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Y
G
87 N 50BF 50/51OC
49
Therm.
87O
o/a Diff51OC
50/51
OC
YY
YY
51
OC
60
FL81
Freq.rel.
50
Ac.Eneg51/67
OC(Idm/dir.)
50
O.C
87G
Gen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S
100%GFP
50THD
100%GFP
+ REX0060
78Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37
Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.
64S
100%GFP + REX0061
UnitX
for.
46
Neg.Pha.
Diff.rel. Brk.flr. OC Therm
Stator Thermal Overload
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Y
G
87 N 50BF 50/51OC
49
Therm.
87O
o/a Diff51OC
50/51
OC
YY
YY
51
OC
60
FL81
Freq.rel.
50
Ac.Eneg51/67
OC(Idm/dir.)
50
O.C
87G
Gen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S
100%GFP
50THD
100%GFP
+ REX0060
78Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37
Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.
64S
100%GFP + REX0061
UnitXfor.
46
Neg.Pha.
-
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-
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Diff.rel. Brk.flr. OC Therm.
Stator Thermal Overload
-
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Y
G
87 N 50BF 50/51 49Therm.
87O
o/a Diff51OC
50/51
OC
YY
YY
51
OC
60
FL81
Freq.rel.
50
Ac.Eneg51/67
OC(Idm/dir.)
50
O.C
87G
Gen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S
100%GFP
50THD
100%GFP
+ REX0060
78Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37
Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.
64S
100%GFP + REX0061
UnitXfor.
46
Neg.Pha.
Diff.rel. Brk.flr. OC Therm.
Stator Thermal Overload
-
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Y
G
87 N 50BF 50/51 49
87O
o/a Diff51OC
50/51
OC
YY
YY
51
OC
60
FL81
Freq.rel.
50
Ac.Eneg51/67
OC(Idm/dir.)
50
O.C
87G
Gen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S
100%GFP
50THD
100%GFP
+ REX0060
78Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37
Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.
64S
100%GFP + REX0061
UnitXfor.
46
Neg.Pha.
Breaker Failure (50BF)
-
7/28/2019 Generator Protection Class presentation
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87 N
Diff.rel.50BFBrk.flr. OC Therm.
Stator Thermal Overload
-
7/28/2019 Generator Protection Class presentation
121/123
Y
G
87 N 50BF 50/51 49
87O
o/a Diff51OC
50/51
OC
YY
YY
51
OC
60
FL81
Freq.rel.
50
Ac.Eneg51/67
OC(Idm/dir.)
50
BF
87G
Gen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S
100%GFP
50THD
100%GFP
+ REX0060
78Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37
Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.
64S
100%GFP + REX0061
UnitXfor.
46
Neg.Pha.
87 N
Diff.rel.50BFBrk.flr. OC Therm.
Stator Thermal Overload
-
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Y
G
87 N 50BF 50/51 49
87O
o/a Diff51
OC
50/51
OC
YY
YY
51
OC
60
FL81
Freq.rel.
50
Ac.Eneg51/67
OC(Idm/dir.)
50
BF
87G
Gen.st.dif
50
Neg.Pha.
49
Therm.
59N
O.V
64S
100%GFP
50THD
100%GFP
+ REX0060
78Out of step
21
Udr.Imp.pro.
32
Rev. Pow.
37
Under curr.
40
FIELD.EXCIT
24
OVER EXCIT
27
UND.VOL.
59
OVER.VOL.
81
FREQ.
64S
100%GFP + REX0061
UnitXfor.
46
Neg.Pha.
-
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